Bsft.EventAggregator.Saga.EFCore 2.2.0

Bsft.EventAggregator.Saga.EFCore

The relational persistence of the Bsft.EventAggregator.Saga family: saga state and durable timeouts in the application's own DbContext, with the state advance of a step and the reminders it scheduled committed in one SaveChangesAsync.

Install

dotnet add package Bsft.EventAggregator.Saga.EFCore

Requires Bsft.EventAggregator.Saga (pulled transitively) and Microsoft.EntityFrameworkCore plus Microsoft.EntityFrameworkCore.Relational. It brings no provider of its own: the application supplies the DbContext and therefore the provider.

Register

public class AppDbContext : DbContext, ISagaTimeoutDbContext
{
    public DbSet<SagaStateEntity> SagaStates => Set<SagaStateEntity>();
    public DbSet<SagaTimeoutEntity> SagaTimeouts => Set<SagaTimeoutEntity>();

    protected override void OnModelCreating(ModelBuilder modelBuilder) =>
        modelBuilder.ApplyConfigurationsFromAssembly(typeof(ISagaDbContext).Assembly);
}

services.AddBsftSaga();
services.AddBsftSagaEFCoreWithTimeouts<AppDbContext>();

// state only, timers stay in memory
services.AddBsftSagaEFCore<AppDbContext>();

Both methods replace registrations AddBsftSaga made, so they are called after it. The context must implement ISagaDbContext for AddBsftSagaEFCore<TContext> and ISagaTimeoutDbContext for AddBsftSagaEFCoreWithTimeouts<TContext>, and its model must carry SagaStateEntityConfiguration and SagaTimeoutEntityConfiguration — the indexes they declare are not cosmetic, they are what makes the pending-name rule and the dispatch claim work. Until 1.3.5 the same wiring was reached through UseDbProvider<TContext>() on the options object; that made the choice of store a property of a configuration record and is gone.

Configure

Validation: none of its own — the constructor guards reject a null service collection, and a context that does not implement the required interface is a compile error rather than a startup one.

Extend

IEFCoreSagaStore and IEFCoreSagaTimeoutStore name the EF-backed implementations behind ISagaStore and ISagaTimeoutStore, so a host can resolve or replace exactly the relational store without touching the engine's provider-agnostic contracts. IEFCoreSagaTimeoutStore.IsStagingIntoWindow reports whether the next write would join an open persistence window, which is what makes the atomic path observable from the outside.

ISagaDbContextAccessor exposes the context of the open persistence window. EFCoreSagaPersistenceWindow implements it and ISagaPersistenceWindow at once, on purpose: whoever opens the window is the only component that can know which context is current, and splitting the two would force the stores to depend on a concrete class to reach the setter. Replace the pair to stage saga writes into a unit of work the application already owns.

Documentation

Topic page: docs/saga.md. Conventions: docs/package-conventions.md.